Postage meters and other value printing devices (e.g. parcel registers, tax stamp meters, encrypted indicia printing systems, etc.) print indicia that represent monetary values. A prime concern in the design of such devices is security of the revenues represented by the indicia. Revenue security has also been a major consideration in the design of the indicia itself. From the beginning, information contained in the indicia has been used for the purpose of verifying validity of the indicia, preventing counterfeiting or misuse, and so forth.
A specimen postage meter indicia according to prior art is shown in FIG. 1. The indicia, generally indicated by reference numeral 20, includes an ornamental portion 22 in the form of an American eagle, a column of stars 24, comprising thirteen stars, a postage amount field 26 and a postmark field 28.
Box 30 defines the boundary of postage amount field 26. Postage amount field 26 includes a printed postage amount 32. It will be appreciated that the legend "SPECIMEN" as shown within postage amount field 26 of specimen indicia 20 is, in actual practice, replaced by a legend such as "U.S. POSTAGE".
Ring 34 defines the boundary of postmark field 28. Postmark field 28 includes origin city designation 36, origin state designation 38 and date 40. In practice postmark field 28 often includes an origin zip code designation in addition to or instead of city designation 36 and state designation 38.
Indicia 20 also includes a meter serial number 42.
As is well known to those skilled in the art, indicia 20 is commonly produced by a rotary or flat-bed printing mechanism using a metal die. For any given die, indicia 20 is invariant except for date 40 and postage amount 32. Under postal regulations, date 40 is to be reset each day so that indicia 20 reflects the date on which the mailpiece is to be submitted to the Postal Service. Postage amount 32 also will vary, the amount depending on the weight, class of service, applicable discounts and other characteristics of the mailpiece to which the indicia is applied. Standard postage meters include means for changing the settings of date 40 and postage amount 32 and also means for accounting for each postage amount 32 that is included in an indicia. The invariant elements of indicia 20, being those other than date 40 and postage amount 32, will sometimes be referred to as the "fixed elements" of indicia 20.
The significance in terms of revenue security of the elements of indicia 20 are well known to those skilled in the art and so will not be discussed in detail. However, it should be noted that some portions of the fixed elements of indicia 20 are specifically designed to make difficult the counterfeiting of indicia 20. Those portions, which are difficult to accurately reproduce by unauthorized means, are referred to as "tells".
With the advent of microprocessors and of dot matrix printers such as ink jet, LED, thermal head or dot matrix pin printers, systems were developed to include in value indicia variable information in addition to date and monetary amount. For the most part the additional information is intended to reinforce the revenue security of the value printing system.
For instance, U.S. Pat. No. 4,835,713 to Pastor (assigned to the assignee of this application), teaches means for defining validating information in terms of a dot matrix, for image transforming that matrix and then for printing the image-transformed dot matrix as part of the indicia. The '713 patent also teaches printing of an alphanumeric array, or a serialized bar code, corresponding to the image transformed matrix. In co-pending application of Pastor, Ser. No. 245,479, filed Sept. 19, 1988, now U.S. Pat. No. 4,949,381 (assigned to the assignee of this application), the image transformed matrix is printed in bit mapped form.
In U.S. Pat. Nos. 4,637,051, to Clark, 4,641,346 to Clark et al. 4,641,347 to Clark et al., 4,829,568 to Clark et al., and 4,660,221 to Dlugos (all of which are assigned to the assignee of this application) there is taught another apparatus for producing a coded indicia. In this device, the indicia is printed in human readable format, but the dots forming the indicia are modified by voids or displacements or the like in order to produce a coded message that is then decodable to ensure that the coded information is identical to the human readable information of the indicia. Printing the coded message in barcoded form is also taught by these patents. Unlike the present invention, these patents teach modification of, or displacement of dots relative to, variable alphanumeric characters of an indicia rather than modification of, or displacement of dots relative to, the fixed features of an indicia.
In U.S. Pat. Nos. 4,649,266 to Eckert, 4,757,537 to Edelmann, 4,775,246 to Edelmann et al., and 4,725,718 to Sansone and Fougere, and in copending application of Chrosny, Ser. No. 882,871, filed July 7, 1986 (all assigned to the assignee of the present application), the indicia includes encrypted validation information in the form of alphanumeric characters. Copending application of Pastor, Ser. No. 515,531, filed May 29, 1990 (continuation of Ser. No. 245,611, filed Sept. 19, 1988) now U.S. Pat. No. 5,031,215, and assigned to the assignee hereof, discloses numeric characters for presenting encrypted validation information in an indicia.
Copending application of Connell et al., Ser. No. 074,424, filed July 16, 1987, and assigned to the assignee of the present application, now U.S. Pat. No. 4,933,849, teaches selection of one indicia pattern from a plurality of indicia patterns for the purpose of authenticating the indicia.
Copending application of Sansone, Ser. No. 904,522, filed Sept. 5, 1986, and assigned to the assignee of this application, teaches printing of a postage indicia by a dot matrix printer using non-standard print quality to deter attachment of unauthorized printers. In another embodiment, the background of the indicia changes in terms of density as a batch of mail is processed. The disclosure of said application Ser. No. 904,522 is hereby incorporated by reference into this application.
Also to be noted are U.S. Pat. Nos. 3,869,986, to Hubbard and 3,990,362 to Check et al., both assigned to the assignee of this application, in which a conventional postage meter printing mechanism is combined with an ink jet printer or other computer output printer
Another security feature that is relevant to the present application is disclosed in U.S. Pat. No. 4,812,994, to Taylor et al., which is assigned to the assignee of this application. The '994 patent teaches a postage metering system that includes a time-of-day clock. A suitable program allows time limits to be selected such that the metering system is inoperable except during times that are within the selected time limits. The disclosure of the '994 patent is hereby incorporated by reference into this application.